2. Generation Of Electricity Through Tidal Energy

3. Group Members Asad Saleh Hayat Umad Zaib Azmat Ullah Halim Ullah
Sibghat Ullah

4. Power Generation Tidal Hydro Wind Solar Nuclear Fuel fossils
Geothermal

5. What are Tides?
The alternate rising and falling of the sea, usually twice in each lunar day at a particular place, due to the attraction of the moon and sun.
Tides originate in the oceans and progress toward the coastlines where they appear as the regular rise and fall of the sea surface.
Tides are one of the most reliable phenomena in the world.

6. What Is Tidal Power???
The objective of tidal power is to convert the kinetic energy of the waves of water, flowing in the sea to electric energy via Generator.
Tidal power facilities harness the energy from the rise and fall of tides.
Ideal sites are located at narrow channels and experience high variation in high and low tides.
Extracts kinetic energy from moving water generated by tides.

7. Energy from the moon
Tides generated by the combination of the moon and sun’s gravitational forces.
Greatest affect in spring when moon and sun combine forces
Bays and inlets amplify the height of the tide.
In order to be practical for energy production, the height difference needs to be at least 5 meters.
Only 40 sites around the world of this magnitude.
Overall potential of 3000 gigawatts from movement of tides.

8. History of Wave Energy
1799: First patent of a device designed to use ocean waves to generate power
1910: First oscillating water column was built by Bochaux-Praceique to power his house
1940s: Yoshio Masuda experimented with many concepts of wave power
2004: Wave power was delivered to an electrical grid for the first time

10. How it works First generation, barrage-style tidal power plants
Works by building Barrage to contain water after high tide, then water has to pass through a turbine to return to low tide
Sites in France (La Rance), Canada (Annapolis), and Russia
Future sites possibly on Severn River in England, San Francisco bay, Passamaquoddy

11. How it works: Tidal Barrages

12. Tidal Barrage: A series of Water Turbine

13. Parts of TPS
 Barrage
 Turbines
Hydro Generator

14. Barrage
The basin is filled through the sluices and freewheeling turbines until high tide. Then the sluice gates and turbine gates are closed.
They are kept closed until the sea level falls to create sufficient head across the barrage and the turbines generate until the head is again low. Then the sluices are opened, turbines disconnected and the basin is filled again.

15. Tidal Barrage Two types: Utilize potential energy
Tidal barrages are typically dams built across an estuary or bay.
consist of turbines, sluice gates, embankments, and ship locks.
Two types:
Single basin system
Double-basin system

16. Wave Power

17. Some Turbine Types Rim Type Bulb Type Tubular Type
In systems with a bulb turbine, water flows around the turbine, making access for maintenance difficult, as the water must be prevented from flowing past the turbine.
Rim turbines reduce these problems as the generator is mounted in the barrage, at right angles to the turbine blades. Unfortunately, it is difficult to regulate the performance of these turbines and it is unsuitable for use in pumping.
Tubular turbines have been proposed for use some UK projects. In this configuration, the blades are connected to a long shaft and orientated at an angle so that the generator is sitting on top of the barrage.
Tubular Type

18. Tidal Turbines (cont.)
‘SeaFlow,’ a 300 kW prototype turbine was the world’s first offshore tidal turbine and was installed off Lynmouth, Devon in May 2003.
Cost £3.4 million and was funded by a consortium of private companies and the UK and German governments.

20. Tidal Multiple Turbines
Underwater turbines are
by definition out of sight
and it is believed that
their environmental
impact is negligible
thanks to their slow
rotation rates of just 10-
30 revolutions per
minute 10 times slower
than that of ships
propellers). In addition,
tidal turbines do not
affect navigation or
shipping and so there
are no hidden extra
costs to consider.

21. Different Generator Types
Tidal Fences
Tidal Lagoons
Tidal Turbines

22. Tidal Fences
Tidal fences are composed of individual, vertical axis turbines which are mounted within the fence structure, known as a caisson.
Kind of like giant turn styles which completely block a channel, forcing all of the water through them.
Unlike barrage tidal power stations, tidal fences can also be used in unconfined basins, such as in the channel between the mainland and a nearby off shore island, or between two islands.

23. Tidal Fences (cont.)
“A 2.2GW tidal fence using the Davis turbine, was being planned for the San Bernadino Strait in the Philippines to be constructed by the Blue Energy company. The project, estimated to cost $US 2.8 Billion is unfortunately on hold due to political instability”
according to Michael Maser a Blue Energy spokesman.”
Davis Hydro Turbine

24. Tidal Fences (cont.)
Since they do not require flooding of the basin, tidal fences have much less impact on the environment, and are significantly cheaper to install.
Unlike barrage generators, tidal fences have the advantage of being able to generate electricity once the initial modules are installed.
Since a caisson structure is still required, which can disrupt the movement of large marine animals and shipping, there are still ecological concerns

25. Tidal Lagoons
Tidal lagoons are an adaptation of the barrage system. Similar to standard barrage models, tidal lagoons retain a head pond and generate power via conventional hydro- turbines.
The difference is that the conventional barrage designs exploit the natural coast line to minimize barrage length. However, this entails blocking the estuary regardless of how deep it is. This raise the costs considerably.
However, a lagoon, for a low cost can pretty much be built anywhere that there is a high tidal range.
The lagoon has relatively little visual impact, as it is below the high water tide mark and appears like a normal sea wall at low tide.

26. -Tidal Stream Generators-
Very close in concept to traditional windmills
Most popular prototype on the market
Prototype sites include Norway, England, and New York.
In prototype turbines where placed in the East River between Queens and Roosevelt Island.
It is the first major tidal power project in the USA.

27. Tidal Turbines
Proposed shortly after the oil crisis of the 1970s, tidal turbines have only become reality in the last decade, when a 10-15kW 'proof of concept' turbine was operated on Loch Linnhe. Resembling a wind turbine, tidal turbines offer significant advantages over barrage and fence tidal systems, including reduced environmental effects.
Tidal turbines utilize tidal currents that are moving with velocities of between 2 and 3 m/s (4 to 6 knots) to generate between 4 and 13 kW/m2. Fast moving current (>3 m/s) can cause undue stress on the blades in a similar way that very strong gale force winds can damage traditional wind turbine generators, whilst lower velocities are uneconomic.

28. Tidal Turbines (cont.)
Tidal turbines offer significant advantages over barrage and fence tidal systems (and other renewable energy sources):
High energy intensity: A 1MW tidal turbine can access five to ten times as much energy per square meter of rotor than a 1MW wind turbine, resulting in a smaller and potentially lower cost machine.
Minimal environmental impact: tidal turbines are visible enough to be avoided by mariners but they have a low visual impact on the seascape, they produce no pollution or noise and their slow moving rotors which turn at less than one revolution in four seconds (15 rpm) are considered unlikely to harm marine life.
High energy return on energy invested: tidal turbines should offer faster energy payback than most other renewables.

29. -Comparison to Wind Energy-
Tidal Stream generators draw energy in the same basic way wind turbines do
Higher density of water allows a single generator to provide significantly more power
Water speeds of nearly 1/10 the speed of wind can provide the same energy output
Current in water is much more reliable then wind in the air.

30. Environmental/Ecological Concerns
Tidal power generation can offer significant advantages, including improved transportation due to the development of traffic or rail bridges across estuaries and reduced greenhouse gas emissions by utilizing tidal power in place of fossil fuels.
However there are also some significant environmental disadvantages which make tidal power, particularly barrage systems less attractive than other forms of renewable energy.
La Rance, France (240MW)

31. Tidal Changes
The construction of a tidal barrage in an estuary will change the tidal level in the basin. This change is difficult to predict, and can result in a lowering or raising of the tidal level. This change will also have a marked effect on the sedimentation and purity of the water within the basin. In addition, navigation and recreation can be affected as a result of a sea depth change due to increased sedimentation within the basin. A raising of the tidal level could result in the flooding of the shoreline, which could have an effect on the local marine food chain.
Ecological Changes
Potentially the largest disadvantage of tidal power is the effect a tidal station has on the plants and animals which live within the estuary. As very few tidal barrages have been built, very little is understood about the full impact of tidal power systems on the local environment. What has been concluded is that the effect due to a tidal barrage is highly dependent upon the local geography and marine ecosystem.
Wales have been caught in tidal generators.
Fish may move through sluices safely, but when these are closed, fish will seek out turbines and attempt to swim through them. Also, some fish will be unable to escape the water speed near a turbine and will be sucked through.

32. 240MW La Rance France

33. -SeaGen- World’s first large scale commercial tidal stream generator.
First one was installed in the Strangford Narrows (Ireland)
Generates 1.2MW between hours a day
Blades span 16 meters in diameter
gov/renewable_energy/ocean/index.cfm/mytopic=50009

34. -Calculations: Tidal Stream Generators-
P = the power generated (in watts)
ξ = the turbine efficiency
ρ = the density of the water (seawater is 1025 kg/m³)
A = the sweep area of the turbine (in m²)
V = the velocity of the flow
*Power equation is based on the kinetic energy of the moving water*

35. Future Expansion of Tidal Turbines
Tidal Farms. Sets of up to hundreds of tidal turbines working in conjunction.
Potential for giga-watts of power
Marine Current Turbine (MCT) created SeaFlow (300kW), is following up with SeaGen (1MW), which will expand to a 5 turbine tidal farm that will provide 5MW.
The Norwegian company, Hammerfest Strom, believes that they will have their first tidal farm of over 20 second generation devices operational before the end of This would be the 3rd phase of their 'Blue Concept' project and would result in a tidal farm that would produce 10MW of renewable electricity.

36. Advantages No pollution Renewable resource
More efficient than wind because of the density of water
Predictable source of energy vs. wind and solar
Second generation has very few disadvantages
Does not affect wildlife
Does not affect silt deposits
Less costly – both in building and maintenance

37. Disadvantages Presently costly Connection to the grid
Expensive to build and maintain
A 1085MW facility could cost as much as 1.2 billion dollars to construct and run
Connection to the grid
Technology is not fully developed
Barrage style only produces energy for about 10 hours out of the day
Barrage style has environmental affects
Such as fish and plant migration
Silt deposits
Local tides change- affects still under study

38. Pros and cons of both tidal power facilities
Tidal Barrages
Mature technology that has been around for nearly 50 years.
Reliable energy source.
BUT
High costs of construction
Environmental impacts on marine life
Low power output in comparison to other energy source like coal and nuclear power plants
Tidal Current Turbines
Able to utilize both ebb and flood tides.
Tidal current turbines are not large massive dam structure.
Tidal current turbine technology is young in its development.
Installation and maintenance challenges.
Environmental impacts are still being tested.

39. Conclusions
Tidal power is a renewable, potentially zero emission (during operation) energy source.
Tides have the advantage of being completely predictable, unlike solar and wind power.
Different types of Tidal Generators suit different areas and energy needs.
There are environmental concerns that need to be addressed when developing this technology further.